The present invention relates generally to reclaiming processes and more particularly to the process of removing resinous coatings from fibrous products and reclaiming the nitrogenous by-product.
Resin treated fiberglass has been used for many different processes including the manufacture of products such as air filters of the type used in heating and air conditioning systems and asphalt-based roofing systems. One skilled in the art appreciates that the resin referred to in the instant application includes various sizing and binders which may be applied to the glass fibers and products formed therefrom. A certain amount of scrap results in the manufacturing process from nonconforming products, damage, mill ends and the like. Up to now, there has not been an effective and efficient way to remove the resin from the fiberglass. The waste products have been disposed of generally in landfill type environments and amount to a landfill cost of thousands of dollars a day throughout the industry, and the lost opportunity from the re-use of the landfilled materials.
One potential solution to the problem is disclosed in U.S. Pat. No. 4,300,955 to Yount (the xe2x80x9cYount ""955 Patentxe2x80x9d). The Yount ""955 Patent discloses a process for removing resin from resin spun fiberglass of either a continuous or chopped fiber type by passing the resin-coated fiberglass through a treatment tank, removing the glass from the tank, then rinsing any residue therefrom prior to drying, chopping, and recycling the glass into the marketplace. The treatment tank used dye machines that were large tubs filled with phosphoric acid and some with rinse water. The process was adaptable to a large number of types of urea-formaldehyde type resin-coated fiberglass.
The Yount ""955 Patent process has three perceived drawbacks. First, the system as proposed is labor intensive, requiring the physical moving of the fiberglass on a screen from the acid bath to a rinsing bath. Second, the system as proposed is sluggish in removing the resin from the fiberglass. Finally, the recovered glass is difficult to reuse in most manufacturing applications. This renders the untreated glass reusable in low value applications such as paving or for use in filters.
It is thus highly desirable to improve the efficiency by proposing a system that is less labor intensive and more efficient in removing resin from the resin-coated fiberglass.
It is also highly desirable to treat the recovered glass so that it may be used in a wide variety of applications such as reinforcement applications.
The present invention has been developed to provide a method to remove the resin from resin treated fiberglass of either the continuous or chopped fiber type in a more efficient and less labor-intensive process than has previously been developed. This process not only returns virtually one hundred percent of the fiberglass treated to a useable condition, but it also eliminates the cost of disposal as well as the resultant pollution control problems associated therewith.
In accordance with the present invention, the resin-containing fiberglass is passed through a washer/extractor machine that strips the resin from the fiberglass. The washer/extractor machine uses an acid bath to remove the resin from the fiberglass. The fiberglass is then rinsed to remove any residue therefrom prior to drying, chopping, and recycling into the marketplace. The acid and water used in the treatment are separated from the resin using a clarifier. The acid and water are reused in the bath, thereby minimizing waste product. The resin residue may be further processed and used in many other industries, including the fertilizer industry.
In addition, a sizing composition treatment bath may be added to the washer/extractor machine to apply a sizing prior to the dewatering or drying step. The sizing helps to minimize fuzzing and interfilament abrasion that typically occurs with unsized fiberglass fibers. This fuzzing and interfilament abrasion reduces the mechanical properties inherent in the fiberglass.
Other objects and advantages of the present invention will become apparent and obvious from a study of the following description and the accompanying drawing which are merely illustrative of such invention.